Microwave-Assisted Rapid Synthesis of γ-Cyclodextrin Metal–Organic Frameworks for Size Control and Efficient Drug Loading

The micron and nanometer-sized γ-cyclodextrin metal–organic frameworks (γ-CD-MOFs) were successfully synthesized using the microwave technique for the first time for rapid and facile synthesis. Polyethylene glycol 20000 (PEG 20000) was used as surfactant to control the size and morphology of γ-CD-MOFs. The as-synthesized γ-CD-MOFs were characterized using various techniques, including X-ray powder diffraction (PXRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and N2 adsorption. The increment in the reaction time and MeOH ratio dramatically damaged the crystalline integrity of γ-CD-MOFs. Fenbufen was selected as a model drug to evaluate the loading characteristics of γ-CD-MOF crystals. As a result, the nanometer sized γ-CD-MOFs (100–300 nm) showed rapid and higher adsorption (196 mg g–1) of Fenbufen in EtOH when compared with the micron crystals. The adsorption parameters fitted well to a pseudo-second-order kinetic model and chemisorption of Fenbufen was further supported by molecular docking illustrations. In summary, the controlled synthesis of γ-CD-MOFs was successfully achieved by microwave assisted method and resultant crystals were further evaluated for potential drug delivery applications.